noexec on /dev/shm
mzerqung at 0pointer.de
Thu Dec 23 21:52:18 UTC 2010
On Mon, 20.12.10 13:07, Fernando Lopez-Lezcano (nando at ccrma.Stanford.EDU) wrote:
> Jack (the Jack Audio Connection Kit, jackaudio.org) has been using the
> file api (apologies if my wording is not absolutely correct in unix
> terms) on the tmpfs filesystem that is mounted on /dev/shm for a very
> long time (10 years?). "/tmp" is not useful to Jack because Jack's
> internal communication pipes can't be stored in any disk based journaled
> filesystem as the latencies involved in accessing them cause glitches in
> the audio streams handled by Jack.
to be frank I don't really buy this. A FIFO or socket in /tmp should be
fine as long as it is opened with O_NOATIME. The data in the fifo buffers
or the socket buffers never ever touches the disk and hence it is
irrelevant whether it is tmpfs or a real disk.
> I raise this issue because "The API for /dev/shm is shm_open()"
> statement above means to me that in the future there will be no file api
> access to a ram mounted filesystem in Fedora (I understand that this is
> my own conclusion, but I can't see any other given the wording of the
> statement above). Before someone implements that idea, please consider
> the needs of a filesystem in ram for such uses as those mentioned in
> this thread (and that is supported by the Fedora distribution by
> default). Just in case...
This too appears to be a good usecase for XDG_RUNTIME_DIR btw.
Lennart Poettering - Red Hat, Inc.
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